Please pay attention the keyword of "Real time". Unlike what you seem those 'auto focus' laser head which allow one time focus point correction per use. Our RTAF auto focus head is tracking the surface distance real time and it keep changing the height over the job. It is a great feature when you're dealing with a 8x5 plywood that is not flatted. Without help from the RTAF, most of you folks need to find a way to tight up the wood sheet and make it level enough for the laser to engrave or cutting.